The present disclosure relates to a light emitting device.
Alight emitting device using a semiconductor light emitting element such as a light emitting diode LED is highly desired to be made smaller, to have higher light extraction efficiency, higher power and higher reliability in a field such as backlights, illuminations and on-vehicle lights. Especially, a side-view light emitting device for a backlight is highly desired to be made smaller and thinner, and to have higher efficiency and higher power.
For example, Japanese Unexamined Patent Application Publication No. 2005-5433 discloses an optical semiconductor device in which one or more light emitting elements in a square shape in a plan view are arranged at an angle of 45 degrees with respect to an axis perpendicular to a layout surface in a recess of a resin package.
However, as the light emitting device disclosed in Japanese Unexamined Patent Application Publication No. 2005-5433, if a light emitting element in a square shape is arranged at an angle of 45 degrees with respect to the axis perpendicular to the layout surface, a mounting space having at least a width and a height of a diagonal line of a square is needed for the light emitting element. Therefore, in the mounting region for mounting the light emitting element, an area of the light emitting elements arranged per unit area is decreased, causing the luminance of the light emitting device to be reduced.